Geotextiles

Geotextiles are a type of permeable synthetic fabric made from polyester, polyvinyl chloride, polyamide, polyethylene, or propylene among others. Geotextiles are categorised into two types: woven and non-woven with different uses and limitations. As the name suggests, woven geotextiles are woven together using yarn to create a stable weave from warp and weft. Non-woven geotextiles are commonly made using the needle punch method from fibres to create a stable network like a fabric. Geotextiles, depending on the application and site specifications, have six key functions: separation, filtration, drainage, sealing, reinforcement, and protection. What makes geotextiles a favourable material is that it often serves multiple functions, depending on the type of geotextile used. The applications of geotextiles are for a variety of industries such as landfill for separation, highways, mining, railway track beds, river embankments, canal linings and chute drains, slope stabilisation, highway embankments, vegetated retaining walls, or river brank stabilisation. In the case of non-woven geotextiles, its main role is filtration, which prevents soil migration into adjacent materials like drainage aggregate while facilitating water flow. the second function is drainage to allow water to drain from or through low-permeability soils and separation to prevent mixing of dissimilar materials. Third is to provide reinforcement which enhances soil shear strength and erosion control to minimize soil particle movement due to water flow. Woven geotextiles lack permeability and are therefore preferred for applications where they provide stabilisation and reinforcement. In some instances, it also allows us to use a poorer fill quality such as embankments, or soft soils since it provides layers of stability. Due to extremely high tensile strength, woven geotextiles are preferred for applications such as reinforcement of soft soils. The introduction of geotextiles allows for embankments and roads to be built over very weak soils and creation of steeper embankments. Introduction of a layer of geotextiles provides lateral restraint by creating interfacial friction with the soil or aggregate. This friction forces the potential bearing surface failure plane to develop at alternate higher shear strength surfaces, acting as a membrane to support wheel loads.